/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.q2;

import javax.management.*;
import java.io.File;
import java.io.FileFilter;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLClassLoader;

/**
 * Q2 Class Loader (scans deploy/lib directory for new jars)
 *
 * @author <a href="mailto:apr@cs.com.uy">Alejandro P. Revilla</a>
 * @author <a href="mailto:taherkordy@dpi2.dpi.net.ir">Alireza Taherkordi</a>
 * @version $Revision$ $Date$
 */
@SuppressWarnings("deprecation")
public class QClassLoader
		extends URLClassLoader
		implements QClassLoaderMBean, FileFilter {
	File libDir;
	ObjectName loaderName;
	MBeanServer server;
	long lastModified;

	public QClassLoader
			(MBeanServer server, File libDir, ObjectName loaderName,
			 ClassLoader mainClassLoader) {
		super(new URL[]{}, mainClassLoader);
		this.loaderName = loaderName;
		this.libDir = libDir;
		this.server = server;
	}

	public void addURL(String url) throws MalformedURLException {
		addURL(new URL(url));
	}

	public boolean accept(File f) {
		return f.getName().endsWith(".jar");
	}

	public boolean isModified() {
		return libDir.canRead() && lastModified != libDir.lastModified();
	}

	public QClassLoader scan(boolean forceNewClassLoader)
			throws InstanceAlreadyExistsException,
			InstanceNotFoundException,
			NotCompliantMBeanException,
			MalformedURLException,
			MBeanRegistrationException

	{
		if (!isModified() && !forceNewClassLoader || !libDir.canRead())
			return this;
		QClassLoader loader;
		if (server.isRegistered(loaderName)) {
			server.unregisterMBean(loaderName);
			loader = new QClassLoader(server, libDir, loaderName, getParent());
		} else
			loader = this;

		File file[] = libDir.listFiles(this);
		for (File aFile : file) {
			try {
				loader.addURL(aFile.toURL());
			} catch (MalformedURLException e) {
				e.printStackTrace();
			}
		}
		loader.lastModified = libDir.lastModified();
		server.registerMBean(loader, loaderName);
		return loader;
	}

	public void forceNewClassLoaderOnNextScan() {
		this.lastModified = 0L;
	}
}

